var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://ecp:ecp123456@134.175.112.213:27017/ecp_db";
 
MongoClient.connect(url, {useNewUrlParser:true},function(err, db) {
    if (err) throw err;
    var dbo = db.db("ecp_db");
    dbo.collection("product_list"). find({'product_price':{'$lt':10,'$gt':3},'product_reviews':{'$gt':1,'$lt':1000},'product_rating':{'$gt':3.5}}).toArray(function(err, result) { // 返回集合中所有数据
        if (err) throw err;
        console.log(result.length);
        db.close();
    });
});